Remove an empty Tag

Previously I added a large Karajan box set , that is split into 10 volumes. I created a Tag and renamed the albums xyz Box 01 …10 etc

I decided against this approach and removed the box , the Tag was then empty and I deleted it.

Now I want to recreate the Tag I cannot use the same name , I cannot remove the old tag at the album level , if I click on it I get an error showing that the Tag is empty, but I can’t find it to delete it

Each Box ie Album shows 2 Tags but only 1 is active

A bug I think, is there a workaround ?